Hydraulic reciprocating motion device



Jan. 26, 1937. A. E. WEAVER HYDRAULIC RECIPROCATING MOTION DEVICE FiledFeb. 16, 1934 2 Sheets-Shet l INVENTOR. H 112627? E. VVaVezj."

ATTORNEYS Patented Jan. 26, 1937 UNITED STATES PATENT OFFlCE Albert E.Weaver, Indianapolis, Ind.; Midge M.

Weaver administratrix of said Albert Weaver, deceased ApplicationFebruary 16, 1934, Serial No. 711,522

16 Claims.

My invention relates to reciprocating motors particularly of the fluidpressure type.

One of the objects of my invention is to provide a reciprocating motiondevice which is selfcontained, fully automatic and which is operated byfluid pressure, the control of the admission of fluid pressure beingaccomplished without springs and without resort being had to outsidemechanical devices.

Another object of my invention is to provide a reciprocating motiondevice operated preferably by fluid pressure, in which the controlvalves for controlling the admission of fluid pressure to what may betermed the motor part, are locked between strokes of the motor part.

For the purpose of disclosing my invention I have illustrated certainembodiments thereof in the accompanying drawings.

In said drawings Fig. 1 is a more or less schematic view of a type ofreciprocating motion device embodying my invention, showing the parts atthe extremity of the stroke of the motor part in one direction;

Fig. 2 is a similar view of the structure illustrated in Fig. 1, showingthe motor part at the extremity of its stroke in the opposite direction;

Fig. 3 is a schematic view showing a modified form of my invention,wherein the speed of the stroke in one direction may be relativelydifferent from the speed of the stroke of the motor part in the oppositedirection, and

Fig. 4 is a similar view to Fig. 3, showing the parts, however, in theirreversed positions.

Referring first to the structure illustrated in Figs. 1 and 2, I providewhat may be termed a motor member A, a pilot valve B and a control valveC.

The motor member A preferably comprises a cylinder I having operatingtherein a group of spaced apart pistons 2 and 3 operatively connectedtogether to work in unison through the instrumentality of a piston rod4, one end 5 of which is extended through the end of thecylindertoprovide a conne" to "be driven. This cylinderTis provided with a pairof exhaust ports o'rfopenin'gs' 6 and 1 connected by the conduit 8 withays uitable'oil supply source 9. The opposite ends f'f the pistons 2 and3' are provided with stop projections Ill and I I adapted to abutagainst the end s'of the cylinder to leave a clearance between theen dsof the pistons and the ends of the cylinder.

The pilot valve B likewise comprises a cylinder l2 having operatingtherein a pair of pistons I3 and It mechanically connected together by an with the portion piston rod IS on which, intermediate of the pistonsI3 and I4 is a. secondary piston l6. Extensions IT and ll of the pistonrod l5 limit the extent of the stroke, towards the end of the cylinder,of the pistons in either direction.

The control valve C likewise comprises a cylinder I8 having operatedtherein suitably spaced apart pistons I9 and 20 mounted on the pistonrod 2| and likewise mounted on this piston rod 2| is an intermediatesupplemental piston 22. 10 The piston rod II is also extended at itsopposite ends as at 23 and 23' to limit the stroke of the pistons ineither direction.

A pressure device 24 is connected with the supply source 9 and thispressure device is like- 15 wise connected through an inlet pipe 25 withthe cylinder I8 at a point intermediate of its ends. This pressuredevice 24 is likewise connected by the supply pipe 28 and its twobranches 2'! and 28 with the cylinder of the pilot valve B, theconnections being such that one of these branches will be closed by oneof the pistons when the other branch is opened.

A conduit 29 extends from the control valve, in front of the piston I9,to the motor cylinder at a point behind the piston 3 and at the end ofthe cylinder I. A similar conduit 30 extends from the cylinder I8 from apoint in front of the piston 20 to the opposite end of the cylinder Ibehind the piston 2.

The cylinder [3 is connected at one end by the conduit 3| with thecylinder I2 at a point in front of the piston I4 and a similar conduit32 connects the opposite end of the cylinder I8 with the cylinder I2 ata point in front of the piston I3. Intermediate of the conduits 3i and32 the cylinder I2 is connected by conduit 33 with an exhaust conduit 34leading to the supply source 9, and the cylinder I8 is likewiseconnected by the conduits 35 and 36 at the points indicated, with theexhaust 34.

The motive fluid for operating the reciprocating motion device ispreferably oil, although other fluid pressure mediums may be used, suchas gas or water or the like, and thepressure member 24 preferablycomprises a suitable oil pump, taking its supply from the source ofsupply 9 and delivering the oil under pressure to the various parts, asmore fully hereinafter described.

In operation, with the parts shown in the position illustrated in Fig.1, the pressure fluid is admitted to the cylinder I8 through the inletpipe 25. It will be noted that with the parts in the positionillustrated the two pistons I9 and 20 are in their extreme left handposition while ill) the pistons I3 and I4 of the pilot valve are intheir right hand position, and the cylinders 2 and 3 of the motorcylinder I are in their right hand extreme position. With the parts inthe position indicated the conduit 29 leading from the control valve Cto the motor member A is uncovered by the piston I9. Therefore fluidpressure entering the cylinder I 8 through the conduit 25 will passthrough the conduit 29 in-back of the piston 3, thus creating a pressurebehind the piston 3 and driving the same to the left. This movement tothe left is unopposed by, any fluid in the cylinder which is at the leftof the piston 2, because said fluid will exhaust from the portion ofsaid cylinder through the conduits 30 into the cylinder I8 and, with thepistons I9 and 28 in the positions illustrated the exhaust conduit 35will be opened so that this fluid will flow back to the source ofsupply. During this movement to the left of pistons 2 and 3, the pistonsI9 and will be locked in the position illustrated due to the fact thatpressure from the conduit 28 will flow through the cylinder I2 and theconduit 32 behind the piston I9. Due to the fact that the pressure isexerted against one end of the piston structure including the pistonsI9, 20, and 22, this structure will be held against movement. In thisinstance, it will be noted that the parts of this structure are held orlocked against displacement by the active pressure of the pump.Furthermore, due to the fact that as soon as the pistons 2 and 3 starton their movement in either direction, they will close the ports in thecylinder I, opening into the pipes 31 and 38 so that the fluid cannotescape from either end of the cylinder I2 and, as a result, the partsare held against movement by an immovable column of liquid and to thisextent may be said to be pressure-locked. Therefore, during'the ma- J'orportion of the stroke of the pistons 2 and 3,

the pilot valve is locked in its position and the pistons I3 and I4 canmove in neither direction under the influence of vibrations or for anyother cause. Theie pistons are only unlocked when the pistons 2 and 3reach the extremities of their stroke. While I have used in theaccompanying claims the expression pressure-locked as describing thecondition of the pistons as being held against movement, as abovedescribed. it will be understood that this expression is used in bothsenses, namely, the sense where active pressure is exerted formaintaining the parts in position or the sense wherein the liquid columnis sealed in the cylinder for the purpose of preventing movement of thepistons in the cylinder.

As soon, however, as the pistons 2 and 3 have moved to the limit oftheir stroke to the left the conduit 31 extending from the extreme righthand end of the cylinder I2 to the cylinder I, and which upon theinitiation of the movement of the piston 8 to the left had been incommunication with the conduit I, is opened to the right hand and of thecylinder 1. Therefore, pressure (bearing in mind that the control valveand pilot valve B are still in the position shown in Fig. 1), will beadmitted from conduit through cylinder I8, conduit 29 through cylinder Iand conduit 31 behind piston I 3. Therefore, a preponderance of pressureis exerted to move pistons. I3 and I4 to the left or to the positionillustrated in Fig. 2. This opens conduit 21 and closes conduit 23,thereby admitting pressure through the cylinder I2 an. conduit 3I behindpiston 20, and thereby exerting a preponderance'of pressure to movepistons 20 and I9 to the right and to the position illustrated in Fig.2. Attention should be called to the fact that when the piston 2 hasmoved to the extreme position to the left the conduit 38 connecting theleft hand end of cylinder I2 with the cylinder I is opened so that anexhaust back to the source of supply 9 is provided for this end of thecylinder.

With the parts moved to the positions illustrated in Fig. 2 the partsare in position to deliver pressure behind the piston 2 to again re-;verse the movement of the pistons to the right and it will be notedthat as the pistons 2 and 3 move to the right an exhaust is providedthrough the conduit 29, the cylinder I8 and conduit 36 for the righthand side of the cylinder. At the same time the pilot and control valvesare locked against movement during the moveme of the pistons 2 and 3 inthe same manner as has been described with reference to Fig. 1, except,however, that the parts are reversed. That is, pressure is being exertedthrough conduit 21, cylinder I2 and conduit 3I to maintain the controlvalve C in its right hand position and the conduits 31 and 38 are closedas soon as pistons 2 and 3 start to move, thus preventingthe escape oradmission of any fluid under pressure to the opposite ends of pistons I3and I4 and'holding them securely locked against movement.

In Figs. 3 and 4 I have illustrated a modification wherein the movementof the pistons 2 and 3 to the left may be considerably slowed down. Thisstructure is particularly applicable wherein a .work stroke is desiredin one direction only and the period of the return stroke can be varied.In this structure the work stroke would be to the right, while thereturn stroke would be to the left. In other words, in Fig. 3 theapparatus is starting on its return stroke, and in Fig. 4 the apparatusis starting on its work stroke. The two pistons 2 and 3 have arrangedtherebetween a roller 39 which is adapted to be connected to anysuitable mechanism. The movement of the pistons I9 and 28 to the left iscontrolled by an adjustable stop 4I so that the piston I9 may move to acontrolled position to more or less open the inlet to the pipe 29 whenthe pistons I9 and 20 are at the limit of their left-hand stroke. Bycontrolling the size of the inlet to the pipe 29 by piston I9 the flowof oil to the cylinder I behind piston 3 is reduced, therebyconsiderably slowing 1 vide relief valve 42 to permit the excess oildelivered by the pump 24 to pass back into the supply source 9.

In this structure it will be noted that the lower portion of thecylinder I is slotted to accommodate the arm 40. However,'the slottingof this cylinder at this point will not affect the operation of theapparatus except that certain of the oil will exhaust through this slotinstead of through the exhaust pipes 6 and I as in Fig. 1. For certaintypes of apparatus, however, the flow of oil through this slot will notaffect the operation. While I have described the pistons 2 and 3, I3 andI4, and I9 and 20 as separate pistons, in each instance the pistons 2and 3 constitute in effect a single piston; the pistons I3 and I4likewise constitute a single piston including the piston portion I6 andthe pistons I9, 28, and 22 likewise constitute a single piston. It isquite apparent that instead of mounting the pistons on piston rods, asshown, the pistons of the different cylinder could be a unitarystructure with suitable channels or grooves formed therein to providefor the valve operation thereof.

I claim as my invention:

1. A device of the character described, comprising at least threesliding valves each of which is operated by fluid pressure, and fluidpressure connections between said valves by which effective pressure isadmitted to the other valves when one of said valves moves to the limitof its stroke, and by which each of the valves is pressure lockedagainst movement during the movement of any one of the other valves.

2. A device of the character described comprising at least threecylinders, a piston in each of said cylinders, the piston of eachcylinder being pressure-operated, pressure connections between saidcylinders, the piston of each cylinder comprising a valve controllingthe admission of efiective pressure to the other two cylinders, and

said pistons being so disposed that they pressurea lock the pistons oftwo of the cylinders against movement until the piston of the othercylinder has moved to the limit of its stroke.

3. A device of the character described, comprising at least threesliding valves each of which is operated by fluid pressure, fluidpressure connections between said valves by which effective pressure isadmitted to and exhausted from the other valves when one of said valvesmoves to the limit of its stroke, and by which each of the valves ispressure-locked against movement during the movement of any one of theother valves, and means for adjusting the movement of one of said valvesto control the rate of admission of fluid pressure to one of the othervalves without affecting the exhaust rate therefrom.

4. A device of the character described, comprising a least threecylinders, a piston in each of said cylinders, the piston of eachcylinder being pressure-operated, pressure connections between saidcylinders, the piston of each cylinder comprising a valve controllingthe admission of efiective pressure to and exhausted from the other twocylinders, said pistons being so disposed that they pressure-lock thepistons of two of the cylinders against movement until the piston of theother cylinder has moved to the limit of its stroke, and adjustablemeans for adjusting the movement of the piston or one of said valves tovary the rate of admission of fluid pressure to one of said valveswithout varying the rate of exhaustion therefrom.

5. In combination,'a cylinder, a pair of pistons operating therein andadapted to move synchronously, a control valve for said cylinder controlling the inlet and outlet of pressure to the opposite ends of saidcylinder, a pressure operated. pilot valve for controlling the admissionof operating pressure to the control valve, the pistons in said cylinderbeing adapted to control the admission of operating pressure to thepilot valve and'to seal the pilot valve against inlet or outlet ofoperating pressure during the movement of said pistons between theextremities of their stroke.

6. In combination, a cylinder, a pair of pistons operating therein andadapted to move synchronously, a control valve for said cylindercontrolling the inlet and outlet of pressure to the opposite ends ofsaid cylinder, a pressure operated pilot valve for controlling theadmission of operating pressure to said control valve including acylinder and pistons operating therein, conduits extending from thefirst-named cylinder to the opposite ends of said pilot valve cylinder,the pistons in said first-named cylinder controlling the admission ofoperating pressure to said conduits and being adapted to close saidconduits between the limits of the stroke of said pistons.

7. In combination, a cylinder, a pair of pistons operating therein andadapted to move synchronously, a control valve for said cylindercontrolling the inlet and outlet of pressure to the opposite ends ofsaid cylinder, a pressure operated pilot valve controlling the admissionof operating pressure to the said control valve including a cylinder andoperating pistons operating therein, ducts at the opposite ends of thefirst-mentioned cylinder communicating with said control valve, ductsextending from the first-mentioned cylinder to the opposite ends of thepilot valve and the length of the pistons in the first-men tionedcylinder being equal to the distance between one of said control valveducts and one of said pilot valve ducts whereby said pistons will closethe pilot valve ducts except at the limit of the movements thereof.

8. In combination, a cylinder, a pair of pistons operating therein andadapted to move synchronously, a control valve for said cylindercontrolling the inlet and outlet of pressure to the opposite ends ofsaid cylinder, adjustable means for controlling the length of the strokeof said control valve in one direction to control the admission ofpressure to the cylinder without afiecting the exhaust therefrom, apressure operated pilot valve for controlling the admission of operatingpressure to the control valve, the pistons in said cylinder beingadapted to control the admission of operating pressure to said pilotvalve and to seal said pilot valve against the inlet or outlet ofoperating pressure during the movement of the pistons between theextremities of their strokes.

9. In combination, with a work cylinder, a pair of pistons operatingtherein in synchronism, a control valve for controlling the admission ofthe inlet and outlet of operating pressure to the opposite ends of saidcylinder including a cylinder, a valve member operating in said cylinderand controlling the admission of fluid pressure to the opposite ends ofthe work cylinder, a pair of pistons connected to said valve member foroperating the same and controlling the exhaust of operating pressurefrom the opposite ends of said work cylinder, a pilot valve including acylinder and a valve member operating therein and controlling theadmission of operating pressure to the opposite ends of the said controlvalve cylinder, and a pair of pistons connected to said valve member foroperating the same, and connections extending between opposite ends ofsaid pilot valve cylinder and said work cylinder, the pistons in saidwork cylinder controlling the admission of pressure to the opposite endsof said pilot valve cylinder and closing the opposite ends of said pilotvalve cylinder against the inlet or outlet of operating pressure betweenthe extremities of movements of said Work cylinder pistons.

10. In combination, a work cylinder, a pair of pistons operating thereinin synchronism, a control valve for controlling the inlet and outlet ofoperating pressure to the opposite ends of said work cylinder,comprising a cylinder, a pair of synchronously moving pistons in saidcylinder and a valve piston intermediate of said pistons and operatingtherewith, a pressure inlet port to said cylinder, a pair of pressureoutlets from said cylinder communicating with the opposite ends of saidwork cylinder, communication between said inlet and said respectiveoutlets being established by the movement of said valve piston, a pairof exhaust ports in said cylinder, communication being establishedbetween said respective exhaust ports and said outlet ports leading tothe work cylinder by the movement of said pistons, a pilot valvecomprising a cylinder, a pair of synchronously moving pistons in saidcylinder and a valve piston intermediate of said pistons and movingsynchronously therewith, an exhaust outlet in said cylinder, a pair ofoutlets in said cylinder respectively communicating with the oppositeends of said pilot valve cylinder, communication being establishedbetween said outlets and said exhaust by the position of said valvepiston, a pair of pressure inlet ports in said pilot cylinder controlledby the position of the pistons therein, and a second pair of pressureinlet ports at opposite ends of said pilot cylinder communicating withoutlet ports in said work cylinder, said outlet ports in said workcylinder being closed by the pistons thereof except when said pistonshave reached the limits of their movements.

11. In combination, a work cylinder, a pair of pistons operating thereinin synchronism, a control valve for controlling the inlet and outlet ofoperating pressure to the opposite ends of said work cylinder,comprising a cylinder, a pair of synchronously moving pistons in saidcylinder and a valve piston intermediate of said pistons and operatingtherewith, a pressure inlet port to said cylinder, a pair of pressureoutlets from said cylinder communicating with the opposite ends of saidwork cylinder, communication between said inlet and said respectiveoutlets being established by the movement of said valve piston, a pairof exhaust ports in said cylinder, communication being establishedbetween said respective exhaust ports and said outlet ports leading tothe work cylinder by the movement of said pistons, a pilot valvecomprising a cylinder, a pair of synchronously moving pistons in saidcylinder and a valve piston intermediate of said pistons and movingsynchronor-ly therewith, an exhaust outlet in said cylinder, a pair ofoutlets in said cylinder respectively communicating with the oppositeends of'said control valve cylinder, communication being establishedbetween said outlets and said exhaust by the position of said valvepiston, a pair of pressure inlet ports in said pilot cylindercontrolledby the position of the pistons therein, and a second pair ofpressure inlet ports at opposite ends' of said pilot cylindercommunicating with outlet ports in said work cylinder, said outlet portsin said work cyiinder being closed by a working cylinder, a pistonmember operating therein in one direction at a substantially constantrate with full effective pressure on a work stroke, and in the oppositedirection in a timing stroke at a controlled variable rate, a pilotvalve comprising a cylinder and piston therein operated by the liquidpressure effecting the movement of said pistons at the ends oftheirrespective strokes and hydraulically locked by the position of thepistons in said movement, a control valve including a cylinder andpistons, said pilot cylinder on a work stroke, and said control valvebeing hydraulically locked by efiective pressure from said pilot valveduring the operation of said work cylinder piston member.

13. In combination, a work cylinder, a pressure operated piston in saidwork cylinder, a control valve cylinder, a pressure operated pistoncontrol valve in said cylinder, a pilot valve cylinder, a pressureoperated piston pilot valve in said pilot valve cylinder, connectionsbetween said control valve cylinder and said work cylinder controlled bysaid control valve for alternately admitting and exhausting operatingpressure to and from the opposite sides of said 'workpiston, connectionsbetween said pilot valve cylinder and control valve cylinder foradmitting and exhausting operating pressure alternately to and from theopposite ends of said control valve cylinder controlled by said pilotvalve piston, said piston maintaining the inlet pressure sealed in thecontrol valve cylinder during the movement of the pilot valve piston,and connections between the work cylinder and the pilot valve cylinderfor admitting and exhausting pressure to and from said pilot valvecylinder from and to said work cylinder, the piston of said workcylinder maintaining said connections sealed between its strokes.

14. In combination, a work cylinder, a pressure operated piston in saidwork cylinder, a control valve cylinder, a pressure operated pistoncontrol valvein said cylinder, a pilot valve cylinder, a

pressure operated piston pilot valve in said pilot valve cylinder,connections between said control valve cylinder and said work cylindercontrolled by said control valve for alternately admitting andexhausting operating pressure to and from the opposite sides of saidwork piston, means for adjusting the movement of said valve to vary theextent of pressure admitted to one side of said work cylinder withoutvarying the extent of the exhaust from the opposite side of said workcylinder, connections between said pilot valve cylinder and controlcylinder for admitting and exhausting operating pressure alternately toand from the opposite ends of said control valve cylinder controlled bysaid pilot valve piston, said piston maintaining the inlet pressuresealed in the control valve cylinder during the movement of the pilotvalve piston, and connections between the work cylinder and the pilotvalve cylinder for admitting and exhausting pressure to and from saidpilot valve cylinder from and to said work cylinder, the piston of saidwork cylinder maintaining said connections sealed between its strokes.

15. In combination, a work cylinder, a pressure operated piston in saidwork cylinder, a control valve cylinder, a pressure operated pistoncontrol valve in said cylinder, means for adjusting'the stroke ofthe'control valve to vary the extent of the pressure admitted to'oneside of the work cylinder without varying the extent of exhaust from theopposite side of said work cylinder, a pressure operated relief valvefor exhausting excessive pressure developed in said control valvecylinder by the restriction of the extent of pressure to the workcylinder, connections between said control valve cylinder and the workcylinder controlled by said control valve for alternately admitting andexhausting operating pressure to and from the opposite ends of said workcylinder, connections between said pilot valve cylinder and said controlvalve cylinder controlling the admission and the exhaust of pressure toand from said control valve cylinder controlled by said pilot valve, andconnections between said work cylinder and said pilot valve cylinder forcontrolling the admission and exhaust of pressure to and from said pilotvalve cylinder from and to said work cylinder controlled by said workcylinder piston.

16. In combination, a work cylinder having a piston operating therein,ports arranged at the opposite ends of said cylinder, a control valvecomprising a cylinder, a pair of synchronously moving pistons and avalve piston operating therein controlling the admission and exhaustofpressure through the ports in said work cylinder, means for adjustingthe stroke of the control valve piston in one direction to vary the flowof pressure to one of the ports of the work cylinder without affectingthe escape of pressure from the other work cylinder port, a pressureoperated relief valve in said control valve cylinder for permitting theescape of excess pressure from the control valve cylinder when saidvalve restricts the admission of pressure to one of the ports of thework cylinder, a pilot valve for controlling the admission of operatingpressure to the control valve comprising a cylinder and valve pistonsoperating therein, and pressure connections between the pilot valvecylinder and the work cylinder controlled by the position of the pistonin the work cylinder.

ALBERT E. WEAVER.

